Road marker



Dec. 1, 1942. A. A. HORNE 1 2,303,462

- ROAD MARKER I Filed Oct. 4, 1940 4 Sheets-Sheet 1 'IIIIIEZIIIIIIIIEQROAD MARKER Filed Oct 4, 1940 4 Sheets-Sheet 2 Dec. 1, 1942. A. A. HORNE2,393,452 I ROAD MARKER Filed Oct. 4, 1940 4 Sheets-Sheet 3 mum I "Mum"A HIIIIIIITIJITTTTF I l I I M? his: 111;: 1

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ROAD MARKER Filed OO b. 4, 1940 4 Sheets-Sheet 4 a? as ea 76 W I s s s lw a W mw Q M77 Patented Dec. 1, 1942 UNITED STTES EPT 'l QFFICE ROADMARKER Arthur A. Home, Wareham, Mass, assignor to The CalcibriteCorporation, Pawtucket, R. I., a corporation of MassachusettsApplication October 4, 1940-, Serial No. 359,636

3 Claims.

My invention relates to road markers of the type adapted to beincorporated in suitable holes provided therefor in a road.

An object of my invention is to provide a road marker of plasticizedmaterial of a novel shape and provided with suitable means projectingtherefrom to insure that the road marker will be a set cementitious roadmarker having substantially the same coefficient of expansion as theroad into which=it is desired to be inserted se-' cured to said road bya cement also having the same coefficient of expansion as said roadmarker to provide a homogeneous mass when said cement is set comprisingthe adjacent portion of the road, the road marker and the cement, allportions of which have substantially the same coefficient of expansionso as to expand and contract as a unit with changes in temperature.

A further object of my invention is to provide a set cementitious roadmarker which when set may be more readily observed than present types ofroad markers as I preferably provide it with a convex upper wallobservable over a greater area than the fiat upper walls of road markersformerly employed.

To provide means to form pockets for the insertion of cement in the roadhole around the marker to positively bind the marker to the road, Ipreferably provide the side wall of the marker with peripheral flangemeans projecting circumferentially outwardly therefrom providing cementreceiving pockets above said flange means so that cement laid thereinmay rigidly bind the marker against the surface of the road and againstany tendency to have any portions thereof lift up on passage of anyvehicular travel thereover.

To receive a greater portion of binding cement between the lower wallthereof and the bottom of the hole provided therefor in the road, Ipreferably provide the road marker with a concave lower wall and Iprovide said lower wall with locking ribs extending under said concavelower wall, at angles to each other projecting integrally downwardlyfrom said body providing between them cement receiving pockets on thesaid concave lower wall to receive cement therein to positively preventthe marker from turning or 5 twisting as heavy vehicular trafiic passesthereover.

A further object of one embodiment of my invention is to provide a metalprotective 'rimfor the marker constructed of noncorrosive, preferablyresilient material to prevent the marker from chipping adjacent theedges thereof, and to provide a polished metal edge simulative of aframe to supplementally attract the eye of both the pedestrian and thevehicle operator.

The metal rim may also be provided with flange means projectingcircumferentially therefrom for the purpose hitherto mentioned ofgenerally locking the marker to the road, providing cooperating groovemeans on the inner wall thereof, which groove means may be readilyfilled by the plastic material of the marker during my novel method ofmanufacture forming cooperating flange means in the body of the markercontained within said groove means.

A further feature of my invention relates to improvements inmanufacturing a road marker having a metal rim wherein circumferentialflanges are formed in the rim by the expansion of the cementitiousmaterial during its forming and setting operating so that ribs will alsobe formed in the cementitious material projecting into the cooperatinggrooves simultaneously formed on the interior of the rim opposite thethus formed outwardly projecting flanges to provide strength to saidflanges and a greater area for adhesion of the marker to the rim. I mayalso, if desired, provide irregular projections or planchets projectinginwardly from said rim with the cementitious material extending aroundsaid projections and into the holes formed by the nicking-in of saidprojections or planchets.

A further feature of my invention is that '1 preferably employ a roadmarker of a novel type resistant to moisture or other water and spilledgasoline or oil, or road oil, normally present on the road surface. Ihave discovered that such a road marker may be constructed of thehydraulic gypsum cement material described and claimed in Patent#1090525, Hydraulic gypsum cement material and manufacturing the same.issued August 24, 1937, to Robert S. Edwards, but that an improved roadmarker is provided if a suitable oxide pigment, a suitable resinadhesive, and a suitable plasticizer be employed in association withsaid hydraulic gypsum cement material, it being my opinion that areaction takes place between said hydraulic cement material and thepigment oxide to provide a stronger and more desirable road marker.

In addition, the incorporation of the resin adhesive and the plasticizertherein not only provide sufiicient moisture for the setting of the roadmarker, but also render said road marker when set, water resistant andgasoline and oil resistant.

A further object of my invention is to provide a road marker which is apure white in color, a result not possible in standard cements. Theplastioizer also is preferably so regulated as to make the markersuitable for use with low winter temperatures and high summertemperatures.

A further object of my invention is to provide a quick setting cementfor binding the markers to the road, constructed of substantially thesame materials, but with a slightly greater percentage of plasticizer. Ihave also found that in use under the conditions of heat necessary forcutting a suitable hole in the road for the marker and the heat of thecement when applied, that a certain amount of gum or adhesive from boththe cement and marker will melt to provide a tighter bond for the markerto the road.

A further object of my invention is to provide a road marker havingbetter wearing qualities than former types of road markers constructedof rubber, cement, or other material.

These and such other objects of my invention as may hereinafter appearwill be best understood from a description of the accompanying drawings,which illustrate various embodiments of road markers constructed inaccordance with my invention, the method of manufacturing one of saidembodiments and the steps in the method of incorporating my improvedroad marker within a suitable hole in the road.

In the drawings, Fig. l is a plan view of one embodiment of road markerconstructed in accordance with my invention employing a metal retainingrim.

Fig. 2 is a cross sectional view therethrough taken along the line 2-2of Fig. 1.

Fig. 3 is a reverse plan view of the marker shown in Fig. 1.

Fig. 4 is a plan view of the preferred embodiment of my invention.

Fig. 5 is a cross sectional view taken along the line 5-5 of Fig. 4.

Fig. 6 is a reverse plan view of the embodiment of my invention shown inFig. 4.

Figs. 7-10 illustrate steps in the method of manufacturing theembodiment of my invention shown in Figs. 1-3, Fig. 7 being adiagrammatic side elevation illustrating the step of cutting metalstrips of the desired length of the metal binding rim and thesupplemental step of forming planchets projecting integrally from oneside thereof, Fig. 8 being a diagrammatic vertical sectional view of asuitable mold for plasticizing or setting said embodiment with the metalrim formed in circular formationwith the planchets projecting radiallyinwardly thereof and with said rim opposite, a series of verticallyspaced grooves formed in the die, Fig. 9 being a vertical,

sectional view similar to Fig. 8 after a suitable mixture of thecomponent materials of said marker has been inserted in heated,semi-plastic form within the die, and Fig. 10 being a vertical sectionalview similar to Figs. 9 and 10 after. the ram has been so lowered in thedie to form the marker and so cooled to set the marker in the desiredfinished formation.

Fig. 11 is a diagrammatic vertical sectional view taken through aportion of a road and a suitable hole formed therein for the receptionof the marker and having a layer of cement on the bottom thereof andthrough a marker of the type shown in Figs. 1-3 in a position above thehole prior to actual insertion within the hole, the section line throughthe marker being slightly offset from the diameter to more clearlyillustrate the invention.

Fig. 12 is a diagrammatic vertical sectional view similar to Fig. 11after the marker has been inserted within its respective hole.

Fig. 13 is a diagrammatic vertical sectional view similar to Fig. 12after a supplemental amount of a binding material has been inserted inthe spaces between the edges of the hole and the marker.

Fig. 14 is a diagrammatic vertical sectional w'ew similar to Fig. 13,but employing the type of marker illustrated in Figs. 4-6.

In the drawings, wherein like characters of reference generally indicatelike parts throughout, H3 and Hi generally indicate embodiments of roadmarkers constructed in accordance with my invention. Insofar as thenovel structural features of road markers are concerned, they are novelof whatever type of plasticized material may be employed, although, aswill be described later, I preferably employ a set cementitious materialhaving substantially the same coefficient of expansion as the road intowhich the road marker I is desired to be inserted. In order that theroad marker may be more readily observed when in position on the road,than former types of read markers, my improved road markers arepreferably provided with convex upper walls 12 or l2. While the roadmarker itself may be of any desired shape, most types are of generalcylindrical shape, such as a true cylinder orsolid polygon.

So far as I am aware, I am the first to provide means, preferably flangemeans !4 or M projecting outwardly from the side wall IE or 16' thereofcircumferentially of said marker to provide cement receiving pocketsabove said flange means to positively lock the marker to th road when inset position on the road. Said flang means may comprise the verticallyspaced circumferential ribs 14, as in the embodiment of my inventionshown in Figs. 1-4, providing above and between said ribs I4 the cementreceiving pockets 19, or the flange 14', in the embodiment of myinvention shown in Figs. 4-6 projecting circumferentially from the lowerportion of the sid wall i6 providing above the step it? formed betweensaid lower flange portion and the upper portion of the marker side walla cement receiving pocket l9.

While my improved marker may be constructed with a fiat lower wall, asis often desirable in small sizes, I also believe I am the first toprovide a marker having a concave lower wall 20 or 20 for receiving agreater area of cement in the pocket formed thereby to assist in bindingthe lower surface of the marker to the bottom of the road hole and Ialso believe I am the first to provide means 22 or 22' projectingdownwardly from such a concave lower wall 20 or 20' to provide integrallocking ribs projecting downwardly within said concavity, bonding it tothe cement to prevent relative rotation or turning of the marker onpassage of heavy vehicular traffic thereover, in my preferredembodiment, said means comprising the marker ribs 22 extending undersaid lower wall at angles to each other and projecting integrallydownwardly from said body providing cement receiving pockets 23 betweenthem. In the preferred embodiment I preferably employ the two lockingribs 22a or 2211. and 22b or 22b extending diametrically across saidconcave lower wall 20 or 20 at right angles to each other and.projecting integrally downwardly from said body to substantially thelevel of the outer edge of said concave lower wall 20 or 20', said edgebeing also the lower edge of the respective side wall It or it.

The embodiment of my invention shown in Figs. 1-3 includes the metalretaining rim 24 to provide a bright metal edge polished by trafiic tobe more readily observable to the pedestrians and vehicle operators andto prevent chipping of the material of the marker. As stated, the flangemeans projecting outwardly from the side wall of the markercircumferentially thereof comprises in this embodiment, a plurality ofvertically spaced circumferential ribs M projecting outwardly from theside wall is of said rim, said ribs l4 being preferably integrallypressed outwardly from the side wall of said rim and a forming on theinner surface cooperatingly formed vertically spaced circumferentialgrooves 26 adapted to receive the male flanges 28 projecting integrallyoutwardly from the cement body of the marker, the side wall it of saidrim being plasticized to the side wall 32 of said marker body with theouter walls of the flanges 23 projecting integrally outwardly from thebody of the marker being plasticized within said cooperating grooves 26.

It is thus obvious that cement receiving pockets 19 will not only beprovided above the upper circumferential flange, but also that,supplemental cement receiving pockets !9 will be also formed betweeneach respective vertically spaced circumferential flange for positivelyholding the marker flat on the road. In the embodiment of my inventionshown in Figs. 1-3, I preferably provide supplemental means to assist inrigidly securing the metal rim 24 to the body of the marker and for thispurpose I provide the nickedin planchets 34 projecting radially inwardlyat spaced distances through the area of said rim into the body of saidmarker with plasticized material in the body of the marker surroundingsaid planchets and with plasticized material from said body filling theplanchet holes 35.

My invention also relates to improvements in the method of making a roadmarker having such a metal rim 24 as more clearly illustrated in Figs.7-10. Said method comprises forming a metal strip 24 of a lengthsubstantially equal to the desired circumference of the road marker andwhere it is desired to employ the planchets 34 in the rim, nicking-in aplurality of planchets 34 to project from one side thereof and alsotherefore providing the planchet holes 36 from the spaces from which theintegral planchets 34 are nicked-in. While this may be done in anysuitable manner, I have diagrammatically illustrated in Fig. 7 asuitable means for this purpose, which comprises a plurality of rollsfor nicking-in the planchets, comprising an upper hob roll 38 having theprojections 4i] projecting therefrom at spaced intervals adapted to fitinto suitable cooperating female depressions 42 formed in the die roll44 rotating underneath it. A continuous piece of strip material 46 ispassed between said rolls and the roll projections ll! projectdownwardly through the strip of material 46 into the depressions 42 ofthe cooperating roll to nick in the integral planchets 534 whilesimultaneously providing the planchets holes 35. Then, after theplanchets 34 are suitably formed in the strip 46, the strip is cut bymeans of a suitable knife 48 into the desired lengths 24 for the metalrims. If the planchets be not employed, however,'it is obvious that therolls 38 and 8 may be omitted. I then arrange said outoff strip 24 incircular formation to provide a hollow cylinder 58 with the planchets 36projecting radially inwardly thereof, preferably as shown in Fig. 8within a suitable die 52 having a plurality of vertically spacedcircumferential grooves in the lower end thereof opposite the outersurface of the inserted metal rim 24. The lower surface of the die holemay be provided with the convex projections 56 projecting upwardlytherefrom of quadrant shape, providing the grooves 58 between them toshape the locking ribs 22a and 22b on the lower concave wall 28 of themarker extending diametrically across the lower wall of the marker atright angles to each other and projecting integrally downwardly from thebody of the marker to substantially the level of the outer edge of thelower concave wall thereof. The quadrant-shaped projections 56 arepreferably of concave formation to provide the concave lower wall 20 ofthe marker. The cementitious material 60 after it has been heated torender it semi-plastic is then put into the hollow cylinder 53 as shownat 56 in Fig. 9. The plunger 62 is then inserted within the die hole 52under a suitable plasticizing pressure to con fine the cementitiousmaterial 5E! within said hollow cylinder 58 to set and plasticize it asa marker l0 within said hollow cylinder 56 and to the inner surface ofthe wall thereof, the pressure exerted on the plunger 82 beingsufiicient to force the cementitious material radially outwardly againstthe inner surface of the rim to force vertically spaced portions of saidmetal rim 2t radially outwardly into said die grooves 5 to provide theplurality of verticallyspaced circumferential ribs M projectingcircumferentially outwardly from the outer surface of the side wall ofsaid rim simultaneously forming the grooves 26 on the inner surfacethereof as the material is bent outwardly from the inner surface of saidWall and thus also simultaneously forcing said cementitious material 5i!into said thus formed grooves 26 to provide a similar plurality ofvertically spaced circumferential ribs 28 projecting outwardly from theset marker body plasticized to and. within said grooves 26, thecementitious material also being plasticized to the inner surface of theside wall of said metal rim 24. Where planchets 34 are employed, thecementitious material B0 is also forced around said planchets 34 andinto said planchet holes 36 to provide a marker having set cementitiousmaterial around said planchets 34 and within said planchet holes 36binding said marker it to said rim 24. I have shown the annular channel64 around the die 52 provided with an inlet 66 and an outlet tit. Withmost plasticizable'materials a cooling action is required to cause themto become plasticized or set and for this reason cool water may becirculated around said annular chamber 64. For

' other plasticizable materials, however, steam may be employed ifdesired to assist the plasticization,

vulcanization, or other desired setting treatments thereof. It isapparent that the embodiment of my invention shown in Figs. 4-6 withouta rim may be suitably molded and set in a similar press with therespective grooves 55 omitted.

In addition, as stated hitherto, I believe I am the first to provide anew combination, comprising the road surface 79 having a marker ittherein contained within a'suitable pro-formed hole 12 therefor in saidroad'surface and secured'to the edge 14 and base 16 of said hole by asuitable cementitious material 18, with said marker [0, said roadsurface 10 and said cementitious material 18 all having substantiallythe same coefficient of expansion, so that the entire mass of the roadsurface adjacent each marker will expand and contract as a unit withchanges in temperature.

While any suitable cement and any suitable set plasticized marker may beemployed for this purpose as long as they have substantially the samecoemcient of expansion as the road and as each other, I preferablyconstruct my marker and the cement of the materials to be explained inmore detail, which have substantially the same coeflicent of expansionas concrete, road tar or asphalt.

Figs. 11-13 illustrate the actual steps of laying a road marker lconstructed in accordance with my invention in such a hole 12 in a roadsurface Ill. The road surface is first provided with the holes 12 forreceiving the road markers ID of slightly greater size than said roadmarkers. Each hole 12 may be made in the road surface in any manner wellknown in the art, either by a pneumatic drill or by first heating theroad surface and cutting out a cylindrical portion forming the hole 12.A layer 89 of cement I8 is first laid in the base 16 of the hole '12.marker I0, preferably one having the flange means I4 on the side wallthereof, a concave lower wall 20 with the locking ribs 22 hithertodescribed is then lowered within said hole 12 as shown in Fig. 12. Thena supplemental amount of cement 82 is poured into the annular space 84between the side wall 14 of the hole and the side wall I6 of the markerand the cement allowed to set in the road. Where an adhesive substanceis employed in the marker and in the cement and if the cement is appliedhot, the adhesive becomes somewhat molten before setting, tending toform the marker, cement and road surface adjacent the marker into asomewhat homogeneous mass. Any suitable type of adhesive may be employedand I employ the word cement in its broadest sense, comprising anysuitable material for permanently sticking themarker [0 within itsrespective hole 12, whether it comprises a true cement, a mastic, orother type of adhesive. It is obvious that the cement 18 will fill inthe quadrant or other shaped pockets 23 between the ribs Ho Or 221) andwill also exude upwardly in said annular space 84. The cement whichexudes in said pockets 23 forms the quadrant shaped projections 88projecting upwardly therein also of cooperating convex shapecomplementary to the concave shape of the lower wall 29 of the markerwhich are plasticized not only to the side Walls ofthe ribs 22a and22?), but also to the concave lower surface 20 of the marker and haveconvex upper surfaces 90 complementary in general to the concave uppersurface of said mold projections 56 hitherto described and it isapparent that these projections 88 will positively abut the ribs 22a and22b and thereby prevent any turning movement of the marker on passage ofheavy vehicular traffic thereover. While a supplemental amount of cementmay be poured in the annular space 84 after the marker is laid, ifdesired, it is obvious that when said annular space is filled as shownin Fig. 13 at 82, that cement projections 92 are also formed above eachrespective flange means I4, and are also plasticized to the uppersurfaces of each respective The flange means and the sidewall l6 of themarker to provide rigid set means above each respective flange M topositively hold the marker flat on the road against any'tendency ofheavy vehicular trafiic to raise the marker from the road as is oftencaused by the suction of pneumatic tires passing thereover, or when abrake is suddenly applied to a fast moving vehicle. I have shown inFigs. 11-13 the marker shown in Figs. l-3 set in the road, and I haveshown in Fig. 14 the embodiment of marker shown in Figs. 4-6 thus set inthe road with a singl annular projection 92' overlying the step 18' tohold the marker flat on the road. As also shown in Figs. 11-14, as theupper surface of the markers is convex as at l2, it will provide a crownto make the road marker visible over a greater area and not impede thepassage of vehicle traflic thereover. It is also apparent that such ashape prevents snow plows, or other road scraping devices from abuttingagainst a straight edge of a marker'to tend to lift it from the road,the convex surfaces merely slightly lifting the snow plow, or otherscraper as it passes thereover.

In the prior art, great difliculty has been experienced with both metaland rubber road markers as they do not expand evenly with the road onchanges in temperature and thus tend to work out in time. With such anuneven expansion, water is apt to seep in between the road hole andmarker, which, when the road is frozen tends to cause the usual frostcracks in the road surface. While it has been suggested to make roadmarkers out of cement, in most instances it is desirable to have whiteroad markers and it has been found impossible to make a pure white outof Portland or other common cements now on the market. Great diflicultyhas been also experienced in providing a road marker which is resistantnot only to the elements, but to other materials normally on traveledroads, such as water or moisture, spilled gasoline or oil from vehicles,or road oil, where employed, and I have endeavored to provide a roadmarker constructed of a suitable set cementitious material which iswater resistant and gasoline and oil resistant and at the same time hasthe desired adhesive and wearing qualities and substantially the samecoefficient of expansion as concrete, road tar or asphalt of which roadsare usually constructed to expand and contract evenly therewith onchanges in temperature to overcome the objections of the road markers inthe prior art as described above. I have found for this purpose thathydraulic gypsum cement material described in Patent No. 2,090,625 forHydraulic gypsum cement material and manufacturing the same, issuedAugust, 24, 1937, to Robert S. Edwards of Milton, Massachusetts, is sucha desirable material. As said material has not as yet acquired a tradename known in the art, although it is now sold under the nameCalcibrite, for shortness of description in the specification and claimsI will refer to this material as Edwards phospho-gypsum cement and wheresuch a phrase is employed henceforth in the specification and claims itwill refer to the hydraulic cement covered and claimed in said Edwardspatent. Cement made from natural rock, gypsum and cement made fromanhydrite, as described in said patent may be alternatively employed.Such a material when used alone is not as oil resistant, gasolineresistant, or water resistant as desirable. I have also discovered thatsuch a material may readily have an oxide pigment incorporated thereinto impart the desired color thereto, and I believe that a certainreaction takes place between such an oxide pigment and the cement itselfduring setting, as to improve the wearing and other qualities of themarker or cement if such materials be employed as the base for themarker or cement. A certain amount of water is also required to initiatethe starting of the setting of the cement, suflicient water to completethe setting being furnished by the atmosphere. To prevent any excess ofwater from adversely afiecting the cement or marker and hence themoisture resistant characteristics of the set cement or marker and toimprove the resistance of the set marker and cement against gasoline,steam, or other waste materials which are often spilled on the roadsurface and to act as an adhesive bond, I preferably, in association,with the pigment employ a suitable resin adhesive and also preferablyemploy in association therewith a suitable plasticizer. Whether theadhesive and/or plasticizer react with the Edwards phospho-gypsumcement, or the pigment oxide is not known, but I have found byexperience that a marker constructed of these materials when set, or acement so constructed for binding the marker to the road, when set hasthe desirable characteristics of a suitable marker or cement for all ofthese purposes. The resin adhesive is preferably ground fine. TheEdwards phospho-gypsum cement is graded from down to .325 mesh. Thepigment oxide is in powder form. The resin adhesive, the Edwardsphospho-gypsum cement and the pigment oxide are first measured orweighed. They are then put in asteam jacketed mixer in suitableproportions, and after the plasticizer is then added, heated up to200-300 F. While they are being mixed by this heat treatment thepulverant materials are rendered semiplastic to provide the semi-plasticmass 60 to be inserted in the die 52 in the manner hitherto explained.If desired, steam under pressure may be inserted in the annular jacket64 to initially maintain these materials at this high temperature andthe die 62 is then forced into the mold under a pressure of from 60 to125 tons. I have found that the materials will become set in aboutthirty seconds and if desired cool water may be passed through theannular chamber 64 during this setting operation. The resin adhesivecontains a certain amount of free water even in dry pulverant form and acertain amount of water is contained in the plasticizer and I have foundthat the water derived from the resin adhesive and plasticizer issufficient to initiate sufficient setting of the marker within the die52 in said period of thirty seconds, so that when the complete marker Ishown in Fig. 10 is removed from said mold, it will be in solid, atleast partially set form. If desired, the marker after fifteen secondsmay be thrown into a bath of cold water to complete the setting and/orcooling.

As explained hitherto, the exact reaction which takes place between thedifferent materials and the water is not understood, but with such atreatment the road marker is suitably set for practical purposes as Ihave found from the manufacture of many road markers. I have found inpractice that best results can be obtained in the manufacture of suchroad markers by employing a mixture prior to setting of 50-75% Edwardsphospho-gypsum cement, 12-23% resin adhesive, 15-30% pigment oxide and2-8% of plasticizer. Any suitable resin adhesive, synthetic or natural,of a type to stand summer and winter temperatures when mixed with asuitable plasticizer may be employed. I preferably, however, employ asuitable type of natural resin, which may or may not be fossilized, infact, any suitable type of natural resin described in a book entitledNatural Resins andsold by the American Cyanamid Company, or otherwise. Ihave actually employed Congo gum, pontianak gum,

Manila gum and kauri, and I have also attained good results with asynthetic resin sold under the trade name of Rezyl.

Any suitable type of oxide pigment may be employed, depending on thedesired color of the marker. I have employed titanium dioxide T10: whichI disccvered produces the best white and reacts in a desirable mannerwith the Edwards piiosphcgypsum cement to provide a stronger marker;also zirconium oxide ZrOz for a white marker; ferric oxide FezQe for ared or brown marker; cadmium sulfide CdS for an orange marker; chromeyellows for a yellow marker and other pigment oxides for various otherdesired colors.

I employ the words oxide pigment to include any suitable type ofmetallic pigment derived from its oxide. In many instances the actualoxides are employed in the trade as pigments for certain colors. Forother colors the oxide may be suitably modified to provide the best typeof pigment, as for instance commercial chrome yellows for yellow, orcadmium sulfide for orange.

As a suitable plasticizer, oastor oil, tung oil, beeswax, or othersuitable natural plasticizer may be employed, or any syntheticplasticizers such as tri-cresyl phosphate may also be employed.

Typical formulas which I have employed for making various types ofmarkers are as follows:

Per cent Edwards phospho-gypsum cement 50 Congo gum 20 Titanium dioxide30 Castor oil 3 This will produce a white marker.

Edwards phospho-gypsum cement 66 Pontianak gum 16 Titanium dioxide .04Chrome yellow 14 Tung oil 4 This will produce a yellow marker.

Edwards phospho-gypsum cement '75 Manila gum 12 Cadmium sulfide (orange)l2 Castor oil 4 This will produce an orange marker.

Edwards phospho-gypsum cement 60 Titanium dioxide 20 Congo gum 20 Castoroil 3 This will also produce a white marker.

As also stated, substantially the same mixtures may be employed as acement for setting my improved road marker into the suitable holetherefor formedin the road surface, but as a slightly more plasticcement is desirable, I preferably employ the same materials as employedfor making the marker in substantially the same proportions but increasethe amount of plasticizer employed to 8-14%.

In the actual laying of the road I have attained best results with myimproved marker and cement constructed of Edwards phospho-gypsum cementand the other materials hitherto described, by cutting a hole 12 in theroad after suitably heating the adjacent road surface and pouring thecement at a temperature of between BSD-400 F. This will tend to melt theadhesive both in the road marker and in the cement and effect a betterbond between the road marker and the cement. A discussion of whether theadhesive fills the voids in the marker and adjacent road surfaces, orwhether due to its temperature is melts to provide a tighter bond, isbelieved immaterial, as results have given much better bondingcharacteristics by employing the adhesive hitherto described in properproportions in both the marker and the cement. The amount of plasticizeremployed in both the marker and the cement is regulated by the lowesttemperature in winter and the highest temperature in summer to provide amarker which will still remain plastic and not crack under the coldconditions of winter and not become too plastic to melt and pick up dustparticles under the heat conditions of summer.

I preferably employ Edwards phospho-gypsum cement as I have found thatwhen mixed with the other ingredients it becomes the least water solubleand most suitably set of any cement now on the market and thus has atendency to outlast other types of cement.

also explained, I am enabled by the use of this material and a suitablewhitening pigment to obtain a marker more nearly pure white than anyhitherto provided to thus be more readily discernible to traffic in use,the rubber tires acting as an eraser and cleaning the marker.

Tests have also proven that the marker itself is somewhat stronger thanmarkers constructed of other types of cement and when mixed with thematerials hitherto described will have moisture resistance, oilresistance and gasoline resistance not present in other types ofmarkers.

I have also found that the reaction produced by these materials providessuch a strong structure that there is much less tendency of the markeritself to chip than in markers constructed of other cements. If desired,however, to render the marker less shatterable, a certain amount ofasbestos or other fiber may be incorporated in the mix.

It is understood that my invention is not limited to the specificembodiments shown or methods describedfand that various deviations maybe made therefrom without departing from the spirit and scope of theappended claims.

What-I claim is: I r

a 1. A road marker adapted to be inserted in a recess in a highway andretained therein by cementitious material comprising a set cementitiousbody having substantially the same coeflicient of expansion as the roadinto which it is desired to be inserted, having an upper wall, a sidewall having flange means projecting outwardly therefromcircumferentially thereof at a distance belowthe top thereof, thecrossvseutional area of said marker being substantially P uniform above saidflange means to provide cement receiving pocket means above said flangemeans, and a lower wall having locking ribs of substantial widthextending across said lower wall at angles to each other and projectingintegrally downwardly from said body providing cement receiving pocketsbetween them.

2. A road marker adapted to be inserted in a recess in a highway andretained therein by cementitious materialcomprising a set cementitiousbody having substantially the same coefficient of expansion as the roadinto which it is desired tobe inserted, having an upper wall, a sidewall having flange means comprising a stepped lower portion of greatercircumference than the upper portion above said step, projectingoutwardly therefrom circumferentially thereof providing cement receivingpocket means above said flange means and a concave lower wall having twolocking ribs of substantial width extending diametrically under saidconcave lower wall at right angles to each other and projectingintegrally downwardly from said body to substantially the level of theouter edge of said con- 'cave lower Wall providing cement receivingpockets between them.

3. A road marker adapted to be inserted in a recess in a highway andretained therein by cementitious material comprising a set cementitiousbody having substantially the same coefflcient of expansion as the roadinto which it is desired to be inserted, having an upper wall, a sidewall having flange means projecting outwardly therefromcircumferentially thereof, comprising a stepped lower portion of greatercircumference than the upper portion above said step, providing cementreceiving pocket means above said flange means and a concave lower wallhaving locking ribs of substantial width extending under said lower Wallat angles to each other and projecting integrally downwardly from saidbody providing cement receiving pockets between them.

ARTHUR A. HORNE.

